Medicine (Northwest Academic Centre) - Research Publications

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    Getting RID of the blues: Formulating a Risk Index for Depression (RID) using structural equation modeling
    Dipnall, JF ; Pasco, JA ; Berk, M ; Williams, LJ ; Dodd, S ; Jacka, FN ; Meyer, D (SAGE PUBLICATIONS LTD, 2017-11-01)
    OBJECTIVE: While risk factors for depression are increasingly known, there is no widely utilised depression risk index. Our objective was to develop a method for a flexible, modular, Risk Index for Depression using structural equation models of key determinants identified from previous published research that blended machine-learning with traditional statistical techniques. METHODS: Demographic, clinical and laboratory variables from the National Health and Nutrition Examination Study (2009-2010, N = 5546) were utilised. Data were split 50:50 into training:validation datasets. Generalised structural equation models, using logistic regression, were developed with a binary outcome depression measure (Patient Health Questionnaire-9 score ⩾ 10) and previously identified determinants of depression: demographics, lifestyle-environs, diet, biomarkers and somatic symptoms. Indicative goodness-of-fit statistics and Areas Under the Receiver Operator Characteristic Curves were calculated and probit regression checked model consistency. RESULTS: The generalised structural equation model was built from a systematic process. Relative importance of the depression determinants were diet (odds ratio: 4.09; 95% confidence interval: [2.01, 8.35]), lifestyle-environs (odds ratio: 2.15; 95% CI: [1.57, 2.94]), somatic symptoms (odds ratio: 2.10; 95% CI: [1.58, 2.80]), demographics (odds ratio:1.46; 95% CI: [0.72, 2.95]) and biomarkers (odds ratio:1.39; 95% CI: [1.00, 1.93]). The relationships between demographics and lifestyle-environs and depression indicated a potential indirect path via somatic symptoms and biomarkers. The path from diet was direct to depression. The Areas under the Receiver Operator Characteristic Curves were good (logistic:training = 0.850, validation = 0.813; probit:training = 0.849, validation = 0.809). CONCLUSION: The novel Risk Index for Depression modular methodology developed has the flexibility to add/remove direct/indirect risk determinants paths to depression using a structural equation model on datasets that take account of a wide range of known risks. Risk Index for Depression shows promise for future clinical use by providing indications of main determinant(s) associated with a patient's predisposition to depression and has the ability to be translated for the development of risk indices for other affective disorders.
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    Socioeconomic status and quality of life in population-based Australian men: data from the Geelong Osteoporosis Study
    Brennan, SL ; Williams, LJ ; Berk, M ; Pasco, JA (WILEY, 2013-06-01)
    OBJECTIVE: To investigate the relationship between socioeconomic status (SES) and reported perceptions of quality of life (QOL) in a cross-sectional population-based analysis of a representative sample of Australian men. METHODS: In 917 randomly recruited men aged 24-92 years, we measured QoL in the domains of physical health, psychological health, environment and social relationships, using the Australian World Health Organization Quality of Life Instrument (WHOQOL-BREF). Residential addresses were cross-referenced with Australian Bureau of Statistics 2006 census data to ascertain SES. Participants were categorised into lower, mid, or upper SES based on the Index of Relative Socioeconomic Disadvantage and Advantage (IRSAD), the Index of Economic Resources (IER), and the Index of Education and Occupation (IEO). Lifestyle and health information was self-reported. RESULTS: Males of lower SES reported poorer satisfaction with physical health (OR=0.6, 95%CI 0.4-0.9, p=0.02), psychological health (OR=0.4, 95%CI 0.3-0.7, p<0.001) and environment (OR=0.5, 95%CI 0.3-0.7, p<0.001), although not social relationships (p=0.59). The poorest QOL for each domain was observed in the lower and upper SES groups, representing an inverse U-shaped pattern of association; however, statistical significance was only observed for psychological health (OR=0.5, 95%CI 0.4-0.7, p<0.001). These relationships were similar for IEO and IER. CONCLUSIONS: Men from lower and upper SES groups have lower QOL compared to their counterparts in the mid SES group.
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    Statin and Aspirin Use and the Risk of Mood Disorders among Men
    Williams, LJ ; Pasco, JA ; Mohebbi, M ; Jacka, FN ; Stuart, AL ; Venugopal, K ; O'Neil, A ; Berk, M (OXFORD UNIV PRESS, 2016-06-01)
    BACKGROUND: There is a growing understanding that depression is associated with systemic inflammation. Statins and aspirin have anti-inflammatory properties. Given these agents have been shown to reduce the risk of a number of diseases characterized by inflammation, we aimed to determine whether a similar relationship exists for mood disorders (MD). METHODS: This study examined data collected from 961 men (24-98 years) participating in the Geelong Osteoporosis Study. MD were identified using a semistructured clinical interview (SCID-I/NP). Anthropometry was measured and information on medication use and lifestyle factors was obtained via questionnaire. Two study designs were utilized: a nested case-control and a retrospective cohort study. RESULTS: In the nested case-control study, exposure to statin and aspirin was documented for 9 of 142 (6.3%) cases and 234 of 795 (29.4%) controls (P < .001); after adjustment for age, exposure to these anti-inflammatory agents was associated with reduced likelihood of MD (OR 0.2, 95%CI 0.1-0.5). No effect modifiers or other confounders were identified. In the retrospective cohort study of 836 men, among the 210 exposed to statins or aspirin, 6 (2.9%) developed de novo MD during 1000 person-years of observation, whereas among 626 nonexposed, 34 (5.4%) developed de novo MD during 3071 person-years of observation. The hazard ratio for de novo MD associated with exposure to anti-inflammatory agents was 0.55 (95%CI 0.23-1.32). CONCLUSIONS: This study provides both cross-sectional and longitudinal evidence consistent with the hypothesis that statin and aspirin use is associated with a reduced risk of MD.
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    Psychiatric disorders, psychotropic medication use and falls among women: an observational study
    Williams, LJ ; Pasco, JA ; Stuart, AL ; Jacka, FN ; Brennan, SL ; Dobbins, AG ; Honkanen, R ; Koivumaa-Honkanen, H ; Rauma, PH ; Berk, M (BMC, 2015-04-08)
    BACKGROUND: Psychotropic agents known to cause sedation are associated with an increased risk of falls, but the role of psychiatric illness as an independent risk factor for falls is not clear. Thus, this study aimed to investigate the association between psychiatric disorders, psychotropic medication use and falls risk. METHODS: This study examined data collected from 1062 women aged 20-93 yr (median 50 yr) participating in the Geelong Osteoporosis Study, a large, ongoing, population-based study. Depressive and anxiety disorders for the preceding 12-month period were ascertained by clinical interview. Current medication use and falls history were self-reported. Participants were classified as fallers if they had fallen to the ground at least twice during the same 12-month period. Anthropometry, demographic, medical and lifestyle factors were determined. Logistic regression was used to test the associations, after adjusting for potential confounders. RESULTS: Fifty-six women (5.3%) were classified as fallers. Those meeting criteria for depression within the past 12 months had a 2.4-fold increased odds of falling (unadjusted OR = 2.4, 95% CI 1.2-4.5). Adjustment for age and mobility strengthened the relationship (adjusted OR = 2.7, 95% CI 1.4-5.2) between depression and falling, with results remaining unchanged following further adjustment for psychotropic medication use (adjusted OR = 2.7, 95% CI 1.3-5.6). In contrast, past (prior to 12-month) depression were not associated with falls. No association was observed between anxiety and falls risk. Falling was associated with psychotropic medication use (unadjusted OR = 2.8, 95% CI 1.5-5.2), as well as antidepressant (unadjusted OR = 2.4, 95% CI 1.2-4.8) and benzodiazepine use (unadjusted OR = 3.4, 95% CI 1.6-7.3); associations remained unchanged following adjustment for potential confounders. CONCLUSION: The likelihood of falls was increased among those with depression within the past 12 months, independent of psychotropic medication use and other recognised confounders, suggesting an independent effect of depression on falls risk. Psychotropic drug use was also confirmed as an independent risk factor for falls, but anxiety disorders were not. Further research into the underlying mechanisms is warranted.
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    Excessive daytime sleepiness and falls among older men and women: cross-sectional examination of a population-based sample
    Hayley, AC ; Williams, LJ ; Kennedy, GA ; Holloway, KL ; Berk, M ; Brennan-Olsen, SL ; Pasco, JA (BMC, 2015-07-05)
    BACKGROUND: Excessive daytime sleepiness (EDS) has been associated with an increased risk for falls among clinical samples of older adults. However, there is little detailed information among population-representative samples. The current study aimed to assess the relationship between EDS and falls among a cohort of population-based older adults. METHODS: This study assessed 367 women aged 60-93 years (median 72, interquartile range 65-79) and 451 men aged 60-92 years (median 73, interquartile range 66-80) who participated in the Geelong Osteoporosis Study between the years 2001 and 2008. Falls during the prior year were documented via self-report, and for men, falls risk score was obtained using an Elderly Fall Screening Test (EFST). Sleepiness was assessed using the Epworth Sleepiness Scale (ESS), and scores of  ≥ 10 indicated EDS. Differences among those with and without EDS in regard to falls were tested using logistic regression models. RESULTS: Among women, 50 (13.6%) individuals reported EDS. Women with EDS were more likely to report a fall, and were more likely to report the fall occurring outside. EDS was similarly associated with an increased risk of a fall following adjustment for use of a walking aid, cases of nocturia and antidepressant medication use (adjusted OR = 2.54, 95% CI 1.24-5.21). Multivariate modelling revealed antidepressant use (current) as an effect modifier (p < .001 for the interaction term). After stratifying the data by antidepressant medication use, the association between EDS and falls was sustained following adjustment for nocturia among antidepressant non-users (adjusted OR = 2.63, 95% CI 1.31-5.30). Among men, 72 (16.0%) individuals reported EDS. No differences were detected for men with and without EDS in regard to reported falls, and a trend towards significance was noted between EDS and a high falls risk as assessed by the EFST (p = 0.06), however, age explained this relationship (age adjusted OR = 2.20, 95% CI 1.03-1.10). CONCLUSIONS: For women, EDS is independently associated with at least one fall during the previous year, and this is more likely to occur whilst located outside. Amelioration of EDS may assist in improving functional outcomes among these individuals by reducing the risk for falls.
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    Depression following fracture in women: a study of age-matched cohorts
    Williams, LJ ; Berk, M ; Henry, MJ ; Stuart, AL ; Brennan, SL ; Jacka, FN ; Pasco, JA (BMJ PUBLISHING GROUP, 2014-01-01)
    OBJECTIVES: High levels of disability, functional impairment and mortality are independently associated with fracture and depression, however the relationship between fracture and depression is uncertain. The aim of this study was to investigate whether fracture is associated with subsequent depressive symptoms in a population-based sample of women. DESIGN: A study of age-matched fracture versus non-fracture cohorts of women. SETTING: Barwon Statistical Division, southeastern Australia. PARTICIPANTS: Two samples of women aged ≥35 years were drawn from the Geelong Osteoporosis Study (GOS). The fracture cohort included women with incident fracture identified from radiology reports and the non-fracture cohort were randomly selected from the electoral roll during 1994-1996. OUTCOME MEASURE: Symptoms of depression for women with and without fracture during the 12-month period 2000-2001 were identified by self-report questionnaire based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. RESULTS: A total of 296 women with fracture (12 hip, 48 vertebral, 91 wrist/forearm, 17 upper arm, 7 pelvis, 11 rib, 62 lower leg and 48 other fractures) and 590 women without fracture were included. Associations between fracture and depression differed between younger (≤65 years) and older (>65 years) women. Age and weight-adjusted odds ratio for depression following fracture among younger women was 0.62 (0.35 to 1.11, p=0.12) and 3.33 (1.24 to 8.98, p=0.02) for older women. Further adjustment for lifestyle factors did not affect the results. CONCLUSIONS: This study demonstrated that differences in mood status exist between older and younger women following fracture and that fracture is associated with increased depression in older women. Assessment of mood status in both the short and long term following fracture in the elderly seems justified, with early detection and treatment likely to result in improved outcomes.
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    Excessive Daytime Sleepiness and Body Composition: A Population-Based Study of Adults
    Hayley, AC ; Williams, LJ ; Kennedy, GA ; Berk, M ; Brennan, SL ; Pasco, JA ; Goel, N (PUBLIC LIBRARY SCIENCE, 2014-11-10)
    BACKGROUND: Excessive daytime sleepiness (EDS) is often associated with increased adiposity, particularly when assessed in the context of samples of sleep-disordered patients; however, it is unclear if this relationship is sustained among non-clinical, population-based cohorts. This study aimed to investigate the relationship between EDS and a number of body composition markers among a population-based sample of men and women. METHODS: This study assessed 1066 women aged 21-94 yr (median = 51 yr, IQR 35-66), and 911 men aged 24-92 yr (median = 60 yr, IQR 46-73) who participated in the Geelong Osteoporosis Study (GOS) between the years 2001 and 2008. Total body fat mass was determined from whole body dual-energy X-ray absorptiometry scans, and anthropometric parameters (weight, height, and waist circumference) were measured. Lifestyle and health information was collected via self-report. Sleepiness was assessed using the Epworth Sleepiness Scale (ESS). Scores of ≥ 10 were considered indicative of EDS. RESULTS: Women: After adjusting for age, alcohol intake, antidepressant medication use and physical activity, EDS was associated with greater waist circumference and body mass index (BMI). EDS was also associated with 1.5-1.6-fold increased odds of being overweight or obese. Men: After adjusting for age, alcohol use, physical activity and smoking status, EDS was associated with greater BMI. These findings were not explained by the use of sedative or antidepressant medication. EDS was also associated with 1.5-fold increased likelihood of being obese, independent of these factors. No differences in lean mass, %body fat, or %lean mass were detected between those with and without EDS for men or women. CONCLUSIONS: These data suggest that EDS is associated with several anthropometric adiposity profiles, independent of associated lifestyle and health factors. Among women, symptoms of EDS are pervasive at both overweight and obese BMI classifications; suggesting a need for further clinical examination to assess possible temporal associations with underlying sleep pathology.
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    Suicidal ideation and physical illness: Does the link lie with depression?
    Sanna, L ; Stuart, AL ; Pasco, JA ; Kotowicz, MA ; Berk, M ; Girardi, P ; Williams, LJ (ELSEVIER SCIENCE BV, 2014-01-01)
    OBJECTIVE: Medical illness is a risk factor for suicidality; however, disorder-specific risks are not well-known and these relationships are often explained by major depressive disorder (MDD). We aimed to investigate the relationship between suicidal ideation, MDD and medical illnesses in an age-stratified, population-based sample of men participating in the Geelong Osteoporosis Study. METHODS: Suicidal ideation and medical conditions were self-reported. Medical conditions were confirmed by medical records, medication use or clinical data where possible. MDD was determined using the Structured Clinical Interview for DSM-IV-TR Research Version, Non-patient edition. RESULTS: Of the 907 men, 8.5% reported suicidal ideation. Thyroid disorders (OR 3.85, 95%CI 1.2-12.1), syncope and seizures (OR 1.96, 95%CI 1.1-3.5), liver disorders (OR 3.53, 95%CI 1.1-11.8; younger men only) and alcoholism (OR 2.15, 95%CI 1.1-4.4) were associated with increased odds of suicidal ideation, independent of age and MDD. Major vascular events doubled the odds of suicidal ideation but this was explained by MDD. No association was evident with high medical burden, musculoskeletal disease, metabolic factors, gastrointestinal disorders, headaches, cardiovascular disease, COPD, cancer and psoriasis. CONCLUSION: Health care professionals should focus on identification, assessment and management of suicidal ideation in the medically ill in patients both with and without MDD.
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    Prevalence of excessive daytime sleepiness in a sample of the Australian adult population
    Hayley, AC ; Williams, LJ ; Kennedy, GA ; Berk, M ; Brennan, SL ; Pasco, JA (ELSEVIER, 2014-03-01)
    OBJECTIVES: Excessive daytime sleepiness (EDS) is associated with significant personal and medical burden. However, there is little indication of the impact of these symptoms in the broader population. PARTICIPANTS AND METHODS: We studied 946 men ages 24-92 years (median age, 59.4 [interquartile range {IQR}, 45-73 years]) and 1104 women ages 20-94 years (median age, 50 [IQR, 34-65 years]) who resided in the Barwon Statistical Division, South-Eastern Australia, and participated in the Geelong Osteoporosis Study (GOS) between the years of 2001 and 2008. EDS was defined as an Epworth Sleepiness Scale (ESS) score of ⩾ 10. Lifestyle factors, history of medical conditions, and medication history were documented by self-report. RESULTS: For men, the age-specific prevalence of EDS was 5.1% (ages 20-29 years), 6.4% (ages 30-39 years), 9.8% (ages 40-49 years), 15.5% (ages 50-59 years), 12.0% (ages 60-69 years), 12.0% (ages 70-79 years), and 29.0% (ages ⩾ 80 years). For women, the age-specific prevalence of EDS was 14.7% (ages 20-29 years), 8.7% (ages 30-39 years), 15.0% (ages 40-49 years), 16.0% (ages 50-59 years), 12.6% (ages 60-69 years), 13.2% (ages 70-79 years), and 17.0% (ages ⩾ 80 years). Overall standardized prevalence of EDS was 10.4% (95% confidence interval, 9.7-11.2) for men and 13.6% (95% confidence interval, 12.8-14.4) for women. CONCLUSIONS: The prevalence of EDS increased with age, affecting approximately one-third of those aged ⩾ 80 years. Because EDS has been associated with poorer health outcomes in the older age strata, these findings suggest that routine screening may be beneficial in ongoing health assessments for these individuals. Overall, more than one-tenth of the Australian adult population has EDS, which is indicative of possible underlying sleep pathology.
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    Data Integration Protocol In Ten-steps (DIPIT): A new standard for medical researchers
    Dipnall, JF ; Berk, M ; Jacka, FN ; Williams, LJ ; Dodd, S ; Pasco, JA (ACADEMIC PRESS INC ELSEVIER SCIENCE, 2014-10-01)
    INTRODUCTION: The exponential increase in data, computing power and the availability of readily accessible analytical software has allowed organisations around the world to leverage the benefits of integrating multiple heterogeneous data files for enterprise-level planning and decision making. Benefits from effective data integration to the health and medical research community include more trustworthy research, higher service quality, improved personnel efficiency, reduction of redundant tasks, facilitation of auditing and more timely, relevant and specific information. The costs of poor quality processes elevate the risk of erroneous outcomes, an erosion of confidence in the data and the organisations using these data. To date there are no documented set of standards for best practice integration of heterogeneous data files for research purposes. Therefore, the aim of this paper is to describe a set of clear protocol for data file integration (Data Integration Protocol In Ten-steps; DIPIT) translational to any field of research. METHODS AND RESULTS: The DIPIT approach consists of a set of 10 systematic methodological steps to ensure the final data are appropriate for the analysis to meet the research objectives, legal and ethical requirements are met, and that data definitions are clear, concise, and comprehensive. This protocol is neither file specific nor software dependent, but aims to be transportable to any data-merging situation to minimise redundancy and error and translational to any field of research. DIPIT aims to generate a master data file that is of the optimal integrity to serve as the basis for research analysis. CONCLUSION: With linking of heterogeneous data files becoming increasingly common across all fields of medicine, DIPIT provides a systematic approach to a potentially complex task of integrating a large number of files and variables. The DIPIT protocol will ensure the final integrated data is consistent and of high integrity for the research requirements, useful for practical application across all fields of medical research.